四环素对兔膝骨关节炎负重模型软骨基质金属蛋白酶1表达的影响

Effect of tetracycline on the expression of matrix metalloproteinases-1 in the cartilage of rabbits with knee joint injury caused by load carrying

目的:观察四环素对兔膝骨关节炎负重模型软骨基质金属蛋白酶1表达的影响,探讨其对骨关节炎防治的有效性及其机制。方法:实验于2005-03/05在武汉科技大学医学院药理实验室进行。①分组处理:18只日本大耳白随机分为假手术组,模型组和给药组各6只。模型组和给药组将兔右侧膝关节前交叉韧带切断造成关节不稳定后,以石膏将左后腿固定于腹部,右后腿负重锻炼造成负重损伤,给药组每日给予四环素(35～40mg/kg)灌胃,其他2组给予等量生理盐水。②观察指标:4周后通过大体形态观察了解股骨内髁关节面的病理改变;苏木精-伊红染色观察软骨细胞形态,甲苯胺蓝染色结果观察蛋白多糖和胶原等基质含量;并检测软骨基质金属蛋白酶1水平。结果:18只兔进入结果分析。①大体观察结果:模型组出现软骨的退变,给药组较模型组关节退变为轻(P<0.05)。②关节软骨细胞形态和基质变化:模型组出现软骨表层缺损,表中层细胞明显减少,甲苯胺蓝染色明显减退;给药组仅见表层软骨细胞减少甲苯胺蓝染色较模型组深。③软骨基质金属蛋白酶1水平:假手术组呈阴性表达,给药组阳性表达率低于模型组[(63±6)%,(82±4)%,P<0.01]。结论:四环素可减轻兔膝骨关节炎负重模型的关节退行变性,减少软骨破坏和软骨基质丢失,其作用可能与四环素控制软骨基质金属蛋白酶1表达增高有关。

AIM： To investigate the effect of tetracycline on the expression of matrix metalloproteinases-1 （MMP-1） in cartilage of rabbit with knee joint injury caused by load carrying, and to explore the efficacy and mechanism of tetracycline in the prevention and treatment of osteoarthritis. MEHODS： The experiment was conducted in the Laboratory of Pharmacology, Medical College of Wuhan University of Science and Technology from March to May 2005. （1）Eighteen Japanese Rabbits were randomly divided into sham operation group, model group and treatment group with 6 rabbits in each group. After causing unstable knee by right anterior crucial ligament cutoff in model group and treatment group, the left leg of the rabbits was fixed on abdomen with plaster, and the right leg was subjected to exercise with were gastrically infused with tetracycline （35-40 mg/kg）, weight to cause knee joint injury. Rabbits in treatment group and the other two groups with normal saline. （2）Four weeks later, the pathological changes of cartilage were grossly observed; the morphology of chondrocytes was observed by HE staining; the content of cartilage matrix such as proteoglycan and collagen was detected by toluidine blue staining, and the expression of MMP-1 in cartilage were measured. RESULTS： All 18 rabbits were involved in the result analysis. （1）According to the gross observation, the severity of the cartilage degeneration in treatment group was lesser than that in model group （P 〈 0.05）. （2）In model group, defects on the surface of cartilage were found; ceUs in moderate superficial layer were significantly reduced, and toluidine blue staining was lessened. In treatment group, only cells in superficial layer were decreased. （3）The expression of MMP-1 in cartilage was negative in sham operation group, and the positive rate of treatment group was lower than that in model group [（63%±6）%, （82%±4）%, P 〈 0.01]. CONCLUSION： Tetracycline can lessen the cartilage degeneration, reduce cartilage damage and cartilage matrix loss in rabbit with knee joint injury caused by load carrying by inhibiting the expression of MMP-1.